Display the error message on one line if possible

lib/codeql.js

@@ -41,8 +41,10 @@ class CommandInvocationError extends Error {
         const prettyCommand = [cmd, ...args]
             .map((x) => (x.includes(" ") ? `'${x}'` : x))
             .join(" ");
-        super(`Encountered a fatal error while running "${prettyCommand}".\n` +
-            `Exit code was ${exitCode} and error was:\n` +
+        error = error.trim();
+        const separator = error.includes("\n") ? "\n" : " ";
+        super(`Encountered a fatal error while running "${prettyCommand}".${separator}` +
+            `Exit code was ${exitCode} and error was:${separator}` +
             `${error}`);
         this.exitCode = exitCode;
         this.error = error;